Spring Payload Filter

Demostration of how to use advantages of Java Reflection with Spring RequestBodyAdvice

Requirements

• Maven
• JDK 1.8

Running payload-filter-usage

• mvn spring-boot:run

Projects Description

• payload-filter: this library offers an option to filter a request body with the purpose of clean/filter the desired fields, developed making usage only of Java Reflection.

• payload-filter-usage: demo project showing how to use payload-filter library with Spring Boot.

Usage

• In a nutshell making usage of annotations over the fields the request payload will be filtered.

1 - Add library dependency

<dependency>
  <groupId>br.com.payload.filter</groupId>
  <artifactId>payload-filter</artifactId>
  <version>0.0.1-SNAPSHOT</version>
</dependency>

2 - Implements RequestBodyAdvice interface

• A sample can be found at: br.com.payload.filter.usage.config.RequestBodyAdvice

3 - Add @Filtered annotation to request body

@PostMapping
public User create(@RequestBody @Filtered User payload) {
  return payload;
}

4 - Add desired annotations over the fields

public class User {
  private String id;
	
  @Trim
  private String name;
	
  @Trim
  @Prefix("ROLE_")
  private String role;

}

Results

Request

{
    "id": "15d4s6d4as85dbhfg454545aadsa",
    "name": "Stefany Souza  ",
    "role": "admin "
}

Response

{
    "id": "15d4s6d4as85dbhfg454545aadsa",
    "name": "Stefany Souza",
    "role": "ROLE_admin"
}

Creating filters

Since this is a demostration I've created just three sample filters, but it's possible to create your own filters creating a Annotation and an extending Filter abstract class, like bellow

• Create the annotation, replace @FilteredClass by your Filter.

@FilterClass(FooFilter.class)
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface Foo {
	
	// optional
	int value();
	
}

• Create the filter class

public class FooFilter extends Filter<Integer> {

	@Override
	public Object filter(Object object, Annotation annotation, Object fieldValue) {
		// YOUR FILTER LOGIC
	}
	
	// getting annotation parameters
	private Integer getAnnotationValue(Annotation annotation) {
		Foo foo = (Foo) (annotation);
		return foo.value();
	}

}